Dynamic nuclear polarization with a cyclotron resonance maser at 5 T

Lino R. Becerra; Gary J. Gerfen; Richard J. Temkin; David J. Singel; Robert G. Griffin

doi:10.1103/PhysRevLett.71.3561

Dynamic nuclear polarization with a cyclotron resonance maser at 5 T

Lino R. Becerra, Gary J. Gerfen, Richard J. Temkin, David J. Singel, and Robert G. Griffin

Phys. Rev. Lett. 71, 3561 – Published 22 November 1993

Abstract

DNP (dynamic nuclear polarization) experiments at 5 T are reported, in which a cycoltron resonance maser (gyrotron) is utilized as a 20 W, 140 GHz microwave source to perform the polarization. MAS (magic angle spinning) NMR spectroscopy with DNP has been performed on samples of polystyrene doped with the free radical BDPA (α,γ-bisdiphenylene-β-phenylallyl) at room temperature. Maximal DNP enhancements of ∼10 for ${}^{1}H$ and ∼40 for ${}^{13}C$ are observed and are considerably larger than expected. The DNP and spin relaxation mechanisms that lead to these enhancements at 5 T are discussed.

Received 26 July 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.3561

Authors & Affiliations

Lino R. Becerra, Gary J. Gerfen, Richard J. Temkin, David J. Singel, and Robert G. Griffin

Francis Bitter National Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138